This invention relates to the use of a polyglycolic acid mesh sling. The sling is sewn, e.g., above the pelvic inlet. The method prevents the small bowel descent into the true pelvis. The invention is useful during radiation therapy, e.g. for various pelvic malignancies.
Colorectal carcinoma is the commonest malignancy affecting both males and females in the United States. The American Cancer Society has predicted that approximately 59,000 Americans will die from the disease in 1983. The rectal component is particularly worrisome because of its high incidence of local regional recurrence. Radiation therapy in these cases is limited to 4,500 cGy. This limitation is based on the fear of inducing small bowel enteritis and arteritis (irreversible damage).
Radiation enteritis is also a complication seen in patients receiving irradiation therapy, e.g., for perineal, pelvic, or intra-abdominal malignancies. It is difficult to obtain an accurate incidence but an estimate is that it occurs in about 5% of patients undergoing irradiation for various malignancies. See e.g., Morgenstern L., Thompson R., and Friedman N.: The Modern Enigma of Radiation Enteropathy: Sequelae and Solutions. Am J Surg. 134: 166-172. 1977. Small bowel obstruction has been noted to double from 5%, with a surgical operation alone, to 12% when surgery is combined with postoperative radiation therapy. Risk factors of previous surgery, diabetes, and hypertension are also known to increase the incidence of radiation-associated small bowel injury. There has been no significant advance made in managing or preventing radiation-induced enteropathy over the last few decades.
Prior attempts to solve this problem have included various chemical treatments. Special diets have also been studied in an attempt to reduce radiation enteropathy. See, e.g. Donaldson S., Jundt S., Ricour C., et al: Radiation Enteritis in Children: A Retrospective Review, Clinicopathologic Correlation, and Dietary Management, CANCER 35: 1167, 1975. Radiation enteropathy may occur when the total dose exceeds 4,500 rads or greater. These prior art attempts are experimental. That is, they have no proven clinical benefit.
There is a relatively large incidence of pelvic and perineal recurrence seen in patients with Dukes pathological stage B2, C1, and C2 rectal lesions. The patients are irradiated preoperatively, postoperatively, or by the "sandwich" technique in attempts to control local recurrence. Many of the patients are treated surgically by either low anterior or abdominoperineal resection. This allows the small bowel to descend below the former peritoneal floor postoperatively and it is therefore at risk for radiation-associated injury.
A surgical mesh material, described e.g. in U.S. Ser. No. 606,104 filed Apr. 26, 1984 and entitled "Surgical Rapair Mesh", when used with the surgical procedure of this invention, prevents small bowel descent below the true pelvic inlet and into the true pelvis. The true pelvic inlet is on a line drawn between the sacral promentory and the pubic ramus. The surgical procedure is used after low anterior resection, hysterectomy or abdominoperineal resection. The procedure is also useful in patients with pelvic malignancies. It may also be useful for patients with the need for adjuvant radiotherapy or in those with known pelvic recurrences requiring radiation therapy as part of their management.
This invention is concerned with a textile material which may be either knit or woven. The material can be made from a tissue absorbable material such as polyglycolic acid (herein PGA) fibers. It is to be understood that the term polyglycolic acid is generic to both the homopolymer and to copolymers containing a glycolic acid ester linkage.
The textile material can be a mesh or fabric which has varying amounts of stretch, including zero stretch in the warp or in the weft (filling) direction.
Although the dimensions and weight of the mesh are only limited by the practical size for its intended use, dimensions of from 4.times.4 inches to 10.times.13 inches and weights of 0.75 to 6.5 ounces per square yard can be normally used. Openings in the mesh can range normally from zero to 1/4 inch.
In order to further stabilize the textile material, that is to eliminate horizontal or vertical edge curling and regulate stretch, the material may be heat set by holding both length and width to a specified dimension within a pin or clip frame while exposing it to temperatures of 90.degree. to 175.degree. C. for periods of 30 seconds to 15 minutes, preferably in a vacuum. The material may also be heat set by holding both the length and width to a specified dimension on a heated cylinder while exposing it to temperatures of 90.degree. to 175.degree. C. for periods of up to 4 hours in a vacuum.
The use of the above-described surgical mesh reduces radiation associated small bowel injury, which is a chronic, unrelenting, clinical problem.
This invention provides for the surgical placement of a polyglycolic acid (which may hereafter be abbreviated as PGA) mesh sling to exclude the small bowel from the true pelvis. The invention may allow higher doses of radiation therapy to be delivered to the area of concern in patients at high risk for, or with actual local recurrence of, pelvic malignancies. The technique appears safe and is free of foreign-body sepsis due to the resorbtive qualities of the PGA. At this time, the surgical procedure is not associated with small bowel obstruction or injury.
The technique can be used in all patients at high risk for local recurrence due to pelvic or rectal malignancies in an attempt to achieve better local postoperative control with adjunctive radiation therapy.
This new use for the PGA Mesh solves an old problem for surgeons, namely: how do we prevent small bowel descent into the pelvis after pelvic surgery? Small bowel descent is the limiting factor to postoperative X-Ray therapy (XRT). Use of the PGA mesh enables us to give postoperative XRT without damage to the small bowel.
The problem of radiation enteritis has been solved by the method of using PGA mesh with this invention. Specifically, the method has solved the following questions:
1. Is a PGA mesh capable of keeping the small bowel out of the pelvis? PA0 2. Is a PGA mesh associated with small bowel obstruction? PA0 3. Is a PGA mesh associated with a reduction in GI transit time?